Electrical probe



March 16, 1948. 1 KALoM ELECTRICAL PROBE Filed April l, 1946 :umufo Lawrence l/om Cllozucnlo Patented Mar. 16, 1948 UNITED STATES PATENT OFFICE i Claims.

amended April 30. 1928; 370 0. G. 752i) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to surgical probes and more particularly to electric probes.

In the practice of surgery foreign metal objects in the body of the patient (such as bullets, fragments of shrapnel, pieces of hypodermic needles, etc.) are very difficult to locate and continued probing frequently endangers the health, if not the life, of the patient. Often the surgeon does not know whether he is striking the metal object or bone that may be adjacent to it, since they may both give the same feeling of resistance. This naturally confuses the surgeon, and results in delaying the operation. Frequently there is a tendency on the part of the metal object to slide along the tissue planes, thus making necessary an unusually large incision which is very undesirable.

In my copending patent application, Serial No. 506,460, filed October 15, 1943, now abandoned, and entitled Surgical device, it is pointed out that the prior art devices of which I am aware have never been very successful. The main reason for their lack of success is that they embody electrodes of such type as to necessitate an excessive diametral dimension with the result that as the penetrating portion of the probe progressed beyond the subcutaneous tissue in search of the metal object, it did not readily cutthrough the fascia, fatty tissue, fibrous tissue and muscle. This condition is materially aggravated in cases where the metal object has been within the body for a considerable period of time and has therelfore become encapsulated in a thick, fibrous sheath.

' As was pointed out in the said copending application that another reason for the failure of the prior art devices of which I am aware is that the construction and arrangement of their electrodes is such that they must be contacted by the metal object at a critically precise angle before their function is complete.

It is among the objects of the present invention to provide an electric surgical probe with penetrating qualities which are an improvement over not only the prior patented art, but also the copending application referred to.

Another object is to further improve the ability of the electrodes to function over a relatively wide range of angles, thereby increasing even further the ease with which a foreign metal object may be located.

Still another object is further increased simplicity and decreased cost of manufacture and operation.

The invention, then, comprises the features hereafter fully described and as particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail a certain illustrative embodiment of the invention, this being indicative of but one of a number of ways in which the principle of the invention may be employed.

In the drawing:

Figure 1 is a side elevational view, mostly in section, of the complete .device of the present invention;

Figure 2 is an enlarged elevational view, mostly in section, of the lower end of the device of Figure 1;

Figure 3 is a fragmentary enlarged elevational view of the probe or penetrating portion of the device;

Figure 4 is a view similar to that of the showing of Figure 3, but taken at clockwise rotational right angles with respect to the latter;

Figure 5 is a view similar to those of Figures 3 and 4, but taken at clockwise rotational right angles with respect to the showing of Figure 4; and

Figure 6 is an end view of the penetrating portion of the device.

Referring more particularly to the drawing, the numeral 2 generally designates the probe or penetrating portion of the device of the present invention. More specifically, this element comprises a cylindrical tube of small diameter which is composed of a hard electrically-conductive substance such as indio-platinum, hardened silver, steel, etc. .This tube 2 corresponds in size and shape with a conventional hypodermic needle; that is, its external diameter may (for example) be of the magnitude of approximately 15 mils, with walls approximately 3 mils in thickness and, accordingly, a bore which is approximately.

an enlarged central cylindrical recess 4 the bottom of which has a coniform extension 6 which communicates with the said tube, as shown in Figure 2. A pair of superposed disks 1 of suitable l junction of the cylindrical recess 4 with the coniform extension 6. An elongate rod 8 of an electrically conductive relatively hard metal is disposed to extend throughout the interior of the cylindrical tube 2, and it projects through the disks 1. The projecting end of the elongate rod 8 terminates in an enlarged head 8 which rests atop the upper of the superposed disks 1 and serves as an electrical contact in a. manner, and for a. purpose, which Will later be described.`

The diameter of the elongate rod 8 is considerably smaller than the inside diameter of. the cylindrical tube 2, and a spaced electrically-insulated relationship between these instrumentalities is maintained by means of a suitable insulating medium I0. This electrical insulating medium may acceptably take the form of a suitable resin which is applied as one or more coatings. For this purpose I have found Formvar to be highly satisfactory. the same being the trade name of a polyvinyl formal resin product of the Shawinigan Products Corporation, New York, N. Y., and belonging to a class of *resins known as polyvinyl acetal resins which are prepared by effecting partial or complete hydrolysis of a polyvinyl acetate, followed by (or simultaneously with) reaction of the hydrolysis product with an aldehyde. Such compositions possess high dielectric strength, and are commercially obtainable in plastic form.

Preferably, too, this electrical insulation illls the space between the bottom of the lower of the superposed disks 1 and the bottom of the coniform extension 6 of the cylindrical recess 4.

In addition to maintaining the aforesaid spaced electrically insulated relationship, the electrical insulating medium mentioned cements the tube 2, enlarged head 3 and rod 8 in rm assembled relationship.

The handle portion of the device of the present invention comprises a tubular hash-light case I5 provided with an interior insulating wall I5 and having an interiorly screw threaded bottom portion I8 into which there is fitted an exteriorly screw threaded hollow nipple I1. This hollow nipple I1 is provided with an upper central cylindrical recess I9 and a, communicating lower central cylindrical recess 20.

Disposed within the lower cylindrical recess 20 is a sleeve 22 into which the upper end of the enlarged head 3 of the cylindrical tube 2 is adapted to telescope and lock in any suitable manner, such as the well known Leurlok, a product of Becton and Dickinson which is widely used as a connector between the needle and body portion of a hypoderrnic syringe. More specically, this comprises a plurality of outwardly extending lugs 23 on the upper end of the enlarged head 3 (of the cylindrical tube 2) which are adapted to pass through registering apertures or slots in an inwardly extending ilange 24 at the lower end of the sleeve 22 inthe lower cylindrical recess 20 of the hollow nipple I1. After the lugs 23 have passed the apertures or slots in the flange 24 the enlarged head 3 is rotated to permit the lower surfaces of said lugs to lie above and in contact with the upper surface of said ange.

Disposed in the upper central cylindrical recess I 3 is a thimble 28 having a tubular extension 28 which depends downwardly into the lower cylindrical recess 20. Both the thimble 28 and its tubular extension 29 are made of an electrical insulating medium, for example Bakelite. With' in the thimble 28 there is disposed an electrically conductive coiled spring 3| which makes contact on its lower end with the upper end of a slidable pin 32 which projects through and from the tubular extension 29 and carries on its projecting end a head 33 which is adapted to engage the head 8 on the upper end of the elongate rod 8 in the cylindrical tube 2. The upper end of the coiled spring 3| engages the base of a flash light battery 35 within the flash light case I5.

A ferrule 36 having a depending tubular extension 31 is disposed within the lower cylindrical recess 20 and serves to guide the tubular extension 29 of the thimble 28 into the enlarged central cylindrical recess 4 in the enlarged head 3 on the cylindrical tube 2.

In the foregoing manner electrical conductivity is maintained between the base of the flashlight 35 and the elongate rod 8 within the cylindrical tube 2.

As shown at the top of Figure 1 of the drawings, a short cylindrical sleeve 40 is mounted in the ashlight case I5 immediately above the flashlight battery and within this sleeve 40 there is mounted i a slidable ring 4 I, the latter carrying a bulb socket 42. A suitable bulb 44 is carried in the bulb socket 42 and the said bulb and th upper end of the ashlight case is closed by a translucent or transparent cap 45.

Either the flashlight bulb 44 and/or the cap 45 is colored as to cast a light which is readily distinguishable in the bright, white light of a surgical operating room.

The use of the coiled spring 3| in conjunction with the slidable pin 32 to which it is soldered tends to make a ilrm contact between its head 33 and the head 9 on the upper end of the elongate rod 8. This spring also tends to take up any slack that may exist between the ilashlight battery 35 and the bulb 44. The slide ring 4I permits movement so that the compression of the coiled spring 3I on the flashlight battery and the lamp bulb will take up the slack between these elements.

All joints which communicate with the outside (or atmosphere) are machined to render them waterproof, whereby the complete device of the invention may, without disassembly, be sterilized simply by immersion in a cold sterilizing solution.

As previously mentioned, the'penetrating end, or outer extremity of the cylindrical tube 2 is provided with a, very sharp cutting extremity and actually in so doing it cooperates `with the corresponding end of the elongate rod 8. The shapes of the cutting extremities of these elements constitute the most important feature of the present invention, and the same will be described immediately hereinafter.

As shown in Figures 3, 4 and 5, the operative end of the device of the invention comprises the coextensive termination of the cylindrical tube 2, the interiorly disposed elongate rod 8 and the insulating medium I0 which is disposed therebetween. In addition, two tapering portions are provided, one being of considerably greater angularity than the other, and each extending for approximately one-half the circumference of the cylindrical tube 2, and both of these tapering portions being rounded to provide a convex contour. 'Ihese tapers are indicated at 41 and 48, the latter being the one of greater angularity and conse quently elective to form an aperture in the wall of the cylindrical tubeA 2 which exposes the adjacent surface of the elongate rod 8. These tapering portions 41 and 48 are preferably obtained by resort to simple grinding operations during which the cylindrical tube 2 is partially rotated.

The preparation of the corresponding surfaces of the elements in the manner stated immediately hereinbefore provides what would be a common point formed by the cylindrical tube 2 and the rod 8 except'. for the minute thickness of insulating medium i8 which separates them. The coextension of the sharpened extremity of the rod 8 with the cutting extremity of the tube 2 enables them to bridge a metal object disposed in end-on relationship; while the curvilinear tapering disposed inwardly thereof provides extreme sensitivity in cases where the metal object is `lust outside the range of the relationship stated.

' When the tube 2 and the rod 8 at the extremity of the probe are bridged by a metal object, a circuit is completed from the central terminal 50 of the iiashlight battery 35 to the central contact 5| of the lamp 44, through the lament (not shown) of said lamp, to the outer threaded contact 44 of the lamp, thence through bulb socket 42, ring 4i, to sleeve d0, through case I5, to hollow nipple Il, and to ferrule 36, and sleeve 22 to head 3, to tube 2 and across the bridging metallic body (not shown) to the rod 8, to head 9, head 33, slidable pin 32, spring 3l, and to the base of the flashlight battery 35. The lamp 44 is thus i1- luminated when the tube 2 and rod 8 are bridged by the foreign metallic body. u

I have found that excellent results may be obtained when the cylindrical tube 2 and the elongate rod 8 are composed of cold drawn stock that has been tempered at 1850 F. soas to develop a Brinell hardness value of between No. 580 and N-o. 620. The hardness of the probing extremity of the device is of utmost importance as it has been found that with softer steel probing around a bony area for about ten minutes will render the point quite blunt and therefore not within the objectives sought by the present invention` Other modes of applying the principles of the invention may be employed, changes being made as regards the details described, providing the features stated in any of the following claims, or the equivalent of such be employed.

This application is a continuation-in-part of my copending application Serial No. 506,460, led October 15, 1943, now abandoned.

Having thus described my invention, what I claim as new and wish to secure by Letters Patent is:

1. A surgical probe comprising an electricallyconductive hollow probing needle having a convexly beveled operative probing extremity, said hollow probing needle having an aperture in the convexly beveled porti-on thereof, a single electrode disposed within and electrically insulated from said hollow needle, a portion of said electrode being disposed at the aperture aforesaid and providing a convexly beveled contact surface which is a continuation ofv the convexly beveled portion of said hollow probing needle and which converges .to a point eccentric to the central axis of said needle, said hollow needle and said electrode being constructed and arranged for electrical connection upon being bridged at their outer extremities by contact with a metallic object, and means disposed exteriorly of the operative probing portion of said hollow needle for indicating the completion of an electric circuit through said hollow needle and said electrode. u

2. A surgical probe comprising an electricallyconductive hollow probing needle having an apertured operative probing extremity which is convexly beveled on two circumferentially spaced portions thereof. said hollow probing needle having an aperture in one of the convexly beveled portions thereof, a single electrode disposed within and electrically insulated from said hollow needle and which converges to a point eccentric to the central axis of said needle, a portion of said electrode being disposed at the aperture aforesaid andproviding a convexly beveled contact surface which is a continuation of the convexly beveled portion of said hollow probing needle. said hollow needle and said electrode being constructed and arranged for electrical connection upon being bridged at their outer extremities by contact with a metallic object, and means disposed exteriorly of the operative probing portion of said hollow needle'for indicating the completion of an electric circuit through said hollow needle and said electrode. l

V3. A surgical probe comprising an electricallyconductive hollow probing needle having an apertured operative probing extremity which is convexly beveled on two circumferentially spaced portions thereof, one of said convexly beveled portions having a lower angle of inclination with respect to the axis of said hollow probing needle, said last-named convexly beveled portion having an aperture, a single electrode disposed within and electrically insulated from said hollow needle. a portion of said electrode being disposed at the aperture aforesaid and providing a convexly beveled contact surface which is a continuation of the convexly beveled portion of said hollow probing needle and converging to a point eccentric to the central axis of said needle, said hollow needle and said electrode being constructed and arranged for electrical connection upon being bridged at their outer extremities by contact with a metallic object, and means disposed exteriorly of the operative probing portion of said hollow needle for indicating the completion of an electric circuit through said hollow needle and said electrode.

4. A surgical probe comprising an electricallyconductive hollow probing needle having a convexly beveled operative probing extremity, said hollow probing needle having an aperture in the convexly beveled portion thereof, a single electrode provided with a head and disposed within and electrically insulated from said hollow needle, a portion of said electrode being disposed at the aperture aforesaid and providing a convexly beveled contact surface which is a continuation of the convexly beveled portion of said hollow probing needle, and which converges to a point eccentric tothe central axis of said needle, said hollow needle and said electrode being constructed and arranged for electrical connection upon being bridged at their outer extremities by contact with a metallic object, a combined handle and electrical indicating means connected with said needle including a flashlight case provided with a transparent cap at one end thereof, said case being adapted to retain a battery, and a bulb in electrical connection with said case and said battery, a hollow nipple provided with an internally fitted sleeve connected to the opposite end of said case, a thimble of insulating material provided with a tubular extension located within said nipple, an enlarged head connected to said needle and iltted within said sleeve, a pin slidau bly fitted within said tubular extension, a coil spring. connected to one end of said pin and vcontacting said battery. a head formed integral with the other end oi said pin and adapted to be held in contact with the head of said electrode within said needle whereby completion 'of en electric circuit at the probing portion or said needle is indile of this patent:

8 UNITED sums m'x'mrs Name Dite Watkins Oct. 7, 1890 Cooley Nov. 15, 1938 Willis Oct. 17, 1939 FOREIGN PATENTS Country Date Austria. Apr. 25, 1933 

